Cells

What Cells covers

Cells is examined on Paper 1 of AQA Biology, which covers topics 1 to 4, and on Paper 3, which can draw on any topic. 327 recall questions across 24 subtopics.

The 24 subtopics

Each one has its own page. AQA AS Biology students sit this topic in the first year.

• Cell-surface membrane, nucleus and mitochondriaRecall questions on the structure and function of the cell-surface membrane, the nucleus with its chromosomes, nucleolus and nuclear envelope, and the membranes and role of mitochondria.Open →
• Chloroplasts, Golgi apparatus and lysosomesRecall questions on the DNA and ribosomes of mitochondria and chloroplasts, the internal membranes of chloroplasts, the functions of the Golgi apparatus and its vesicles, lysosomes and ribosomes.Open →
• Ribosomes, endoplasmic reticulum, cell walls and vacuolesRecall questions on ribosome structure and location, rough and smooth endoplasmic reticulum, the cell walls of plants and fungi, and the structure and functions of the plant cell vacuole.Open →
• Cell specialisation, levels of organisation and organelle rolesRecall questions on how cells specialise and form tissues, organs and organ systems, what distinguishes eukaryotic from prokaryotic cells, and applying organelle functions to unfamiliar cases.Open →
• Prokaryotic cell structure and virus particlesRecall questions on the size, ribosomes, circular DNA, murein cell wall, plasmids, capsule and flagella of prokaryotic cells, and the capsid, genetic material and attachment proteins of viruses.Open →
• Optical and transmission electron microscopesRecall questions on how optical microscopes form images, their magnification, resolution and practical advantages, and how a transmission electron microscope forms an image and what it resolves.Open →
• Scanning electron microscopes, magnification and graticulesRecall questions on the scanning electron microscope, the limitations of electron microscopy, resolution and magnification, the magnification formula, and calibrating an eyepiece graticule with a stage micrometer.Open →
• Cell fractionation, homogenisation and ultracentrifugationRecall questions on cell fractionation, why the homogenising solution is cold and buffered, filtration, and how ultracentrifugation separates organelles into pellet and supernatant.Open →
• Order of sedimentation, artefacts and fractionation conditionsRecall questions on the order in which organelles sediment in differential centrifugation, artefacts in microscopy, and why the homogenate must be cold, isotonic and buffered.Open →
• The cell cycle, interphase and the stages of mitosisRecall questions on the cell cycle, DNA replication in interphase, and what happens to chromosomes, the nuclear envelope and spindle fibres in prophase, metaphase, anaphase and telophase.Open →
• Spindle fibres, cytokinesis and uncontrolled cell divisionRecall questions on the role of spindle fibres, cytokinesis, how uncontrolled cell division leads to cancer, how some cancer drugs stop cells dividing, and binary fission.Open →
• Binary fission, viral replication and root tip squashesRecall questions on how circular DNA and plasmids are shared in binary fission, how viruses replicate inside host cells, and preparing stained root tip squashes to find the mitotic index.Open →
• Mitotic index, mitosis stages and size calculationsRecall questions on calculating the mitotic index, the events of each stage of mitosis, and working with standard form, significant figures and estimates when calculating cell size and magnification.Open →
• The fluid-mosaic model and cholesterolRecall questions on the fluid-mosaic model of membranes, intrinsic and extrinsic proteins, glycoproteins and glycolipids, and how cholesterol affects membrane fluidity at high and low temperatures.Open →
• Simple diffusion, facilitated diffusion and membrane proteinsRecall questions on simple diffusion through the phospholipid bilayer and its limits, facilitated diffusion, and how channel and carrier proteins move specific molecules across membranes.Open →
• Osmosis, water potential and active transportRecall questions on osmosis and water potential, the water potential of pure water and solutions, and active transport by carrier proteins using energy from ATP hydrolysis.Open →
• Co-transport in the ileum and adaptations for rapid transportRecall questions on co-transport of sodium ions and glucose into ileum epithelial cells, how glucose reaches the blood, and how surface area, protein numbers and gradients speed transport across membranes.Open →
• Transport rates, dilution series and membrane permeabilityRecall questions on what limits the rates of diffusion, facilitated diffusion and osmosis, finding the water potential of plant tissue with a dilution series, and investigating membrane permeability.Open →
• Antigens, cell recognition and phagocytosisRecall questions on how surface molecules let the immune system identify pathogens, foreign cells, abnormal cells and toxins, antigens and antigen variability, and how phagocytes engulf pathogens.Open →
• Antigen-presenting cells, T cells and clonal selectionRecall questions on lysozymes, the cellular response, antigen-presenting cells, how helper T cells activate cytotoxic T cells, B cells and phagocytes, and clonal selection in the humoral response.Open →
• Antibody structure, agglutination and antigen-antibody complexesRecall questions on the heavy and light chains, variable and constant regions of an antibody, antigen-binding sites, antigen-antibody complexes, and how agglutination helps phagocytes destroy pathogens.Open →
• Memory cells, vaccination and active and passive immunityRecall questions on plasma cells and memory cells, the primary and secondary immune responses, how vaccines give protection and herd immunity, and natural and artificial active and passive immunity.Open →
• HIV structure and replicationRecall questions on the lipid envelope, glycoprotein spikes, RNA and reverse transcriptase of HIV, how it infects helper T cells and integrates into the host genome, and how new particles leave.Open →
• AIDS, monoclonal antibodies, ELISA and clinical trialsRecall questions on how HIV causes AIDS, why antibiotics do not work on viruses, monoclonal antibodies in targeted drugs and diagnosis, the ELISA test, and the ethics and design of vaccine and antibody trials.Open →

What you need to know

Answer each one before you reveal it.

Take Cells further

The same content, four other ways.

Commonly confused

Pairs that lose marks when they are blurred together.

• Magnification vs Resolution

  Magnification: how many times larger an image is than the object. Resolution: the ability to distinguish two close points separately.

• Prokaryotic cell vs Eukaryotic cell

  Prokaryotic cell: a small cellular form lacking membrane-bound organelles. Eukaryotic cell: a cellular form containing a nucleus and membrane-bound organelles.

• Active transport vs Facilitated diffusion

  Active transport: movement against a concentration gradient using energy and carrier proteins. Facilitated diffusion: passive movement down a concentration gradient through membrane proteins.

Questions from this topic

Each one with the model answer underneath.

1. 1

   What is the primary function of the cell-surface membrane?

   Model answer

   It controls the entry and exit of substances into and out of the cell.

2. 2

   Describe the basic structure of the cell-surface membrane.

   Model answer

   It is a partially permeable barrier composed of a phospholipid bilayer with embedded proteins.

3. 3

   What two key roles does the nucleus perform in a eukaryotic cell?

   Model answer

   It contains the genetic material and controls cell activities.

4. 4

   What are chromosomes composed of?

   Model answer

   Linear DNA bound to proteins.

5. 5

   How many nucleoli can be present within a nucleus?

   Model answer

   One or more nucleoli.

6. 6

   What is the function of the nucleolus?

   Model answer

   It is the site of ribosome production.

What is inside Levo

Six ways to work the same material.

Cells revision questions

Is Cells examined at AS in AQA Biology?

Yes. It sits in Papers 1 and 3, which you take in the first year, so it is on the AS paper as well as counting towards the full A level.

What does Cells cover in AQA AS-Level Biology?

24 subtopics: cell-surface membrane, nucleus and mitochondria, chloroplasts, golgi apparatus and lysosomes, ribosomes, endoplasmic reticulum, cell walls and vacuoles, cell specialisation, levels of organisation and organelle roles, prokaryotic cell structure and virus particles, optical and transmission electron microscopes, scanning electron microscopes, magnification and graticules, cell fractionation, homogenisation and ultracentrifugation, order of sedimentation, artefacts and fractionation conditions, the cell cycle, interphase and the stages of mitosis, spindle fibres, cytokinesis and uncontrolled cell division, binary fission, viral replication and root tip squashes, mitotic index, mitosis stages and size calculations, the fluid-mosaic model and cholesterol, simple diffusion, facilitated diffusion and membrane proteins, osmosis, water potential and active transport, co-transport in the ileum and adaptations for rapid transport, transport rates, dilution series and membrane permeability, antigens, cell recognition and phagocytosis, antigen-presenting cells, t cells and clonal selection, antibody structure, agglutination and antigen-antibody complexes, memory cells, vaccination and active and passive immunity, hiv structure and replication and aids, monoclonal antibodies, elisa and clinical trials. Each one has its own page with questions and model answers.

How is Cells organised?

By the AQA 7402 specification, subtopic by subtopic, so it matches the order you are taught it in.